If I understand you right you want all of these desktops (170?) to be able to download some files specified in an XML file.

To use the local filesystem (e.g. save a file) you will need to make an executable. A user loading a SWF in their browser will never have access to downloading and saving a file to the users computer. Flash is designed that way, so you're not worried a website is saving files on your computer (beyond innocent cookies).

You can use Adobe AIR which can save files or use a SWF projector extender like MDM Zinc or Screentime's mProjector. They can do as much and sometimes a lot more than AIR. I use all 3 and I download files in apps (AIR) and desktop (MDM Zinc). All 3 executables can be made for Windows, OSX and Linux.